Without the change build fails on `master` as
https://hydra.nixos.org/build/249125931:
ss.c: In function 'StackHot':
ss.c:38:13: error: storing the address of local variable 'stackOut' in '*stackOut' [-Werror=dangling-pointer=8]
38 | *stackOut = &stackOut;
| ~~~~~~~~~~^~~~~~~~~~~
Blanket `-Werror` tends to break with minor toolchain and dependency
changes. It's a reasonable option to test upstream and use downstream
only if upstream is quick at addressing builds failures. `gcc-13` is
almost a year old.